One source of expense to trucking companies is liability arising from accidents in which a truck runs over a car, while making a right hand turn. As illustrated in FIG. 1, a tractor-trailer 10 rig has a large turning radius, compared with cars, and accordingly must typically pull into the left lane 25 of a road in preparation for making a right hand turn, in order to clear the nearest corner 40. A car 30 that pulls up in the right lane 20 next to the rig 10, is likely to be run over by the truck's rear wheels 15 as the truck turns right, as is evident from the figure.
A number of parties have attempted to develop a system to remedy this problem. One of these systems is disclosed in U.S. Pat. No. 5,781,120, issued to Kucik. Kucik shows an arm that is extended outwardly from the truck to act as a warning to any car that would enter the right hand lane of the road, while the truck was in the process of making a right turn. This arm is controlled by an input device inside the tractor cab. Unfortunately, the patent gives no explanation of how a signal is delivered to the arm mechanism from the input device in the cab. Although a reader might imagine various embodiments, some involving a punch to create a hole in the tractor shell, to permit a wire to be strung out of the tractor, Kucik simply does not address the problem. Perhaps because of this gap in the teachings of Kucik, it does not appear that the product described was ever commercially produced.
Moreover, in the control scheme of Kucik, the arm is directly deployed by the driver of the truck. This may result in the arm not being deployed at times when the driver forgets to actuate the control switch.
Accordingly, there is a continuing need for a tractor-trailer rig right turn warning device that can be controlled from the tractor cab, as Kucik does not disclose how to construct such a device.